Hi,
I have 2 subforms in my main form each of them has its own Autoincrement ID number.
When I try to add new record and filling table fields It showing me an error :The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship.

I know the problem is with the auto increment field that is not updating, any way to do it ??

IF it isn't the case so you have to think how to do your queries updatable! It's NOT by Append or Update queries! It's by changing your SELECT query!

If you want you can describe your query : tables, links and fields from tables and see here what we can do together!

About the forms!

For each control that is displayed in the form have properties! The subform which is located in the form also has properties that you can see them clicking in the respective subform once pressing the right mouse bouton if you are with right handing mouse and choose properties!

In the properties you have to flook for Link master field and link chield field properties!

Those properties do the connection between Main and subform!

Principally In the Chield Field /s we enter information from the main form that concerns the subform! The relation is: the first field from Link Master Fields corresponds to the first field from Link Chield Fields!

You have to be carefull about the information that you type in those fields!

Thanks again Peb, this problem has been solved.
I have another issue that i want one field in the subform to be a combo box when one of the value selected, rest of the fields should be changed to match the selected value.
any idea on how to do it.

Not sure if this is what you are looking for, but here is what I did for a similar situation. What happens in my case is I make a selection from a pull-down list from the combo box, and the price appears in the text box.

I have 2 tables with following fields:

tblrefPartsList is just a list of all the parts and a second column listing the price for each part. It has the following fields:
PartID - Autonumber (PK)
refPart - Text
refCost - Currency

tblTBMPartsCost is the child table that stores all the parts used for each customer. It has the following fields:
TBMID - Number (PK)
PartID - Number (PK) - Same as PartID in tblrefPartsList
PartName - Text - Same as refPart in tblrefPartsList
PartCost - Currency

My subform is based on tblTBMPartsCosts. There are 3 controls on the subform - 1 combo box, and 2 text boxes. The combo box is tied to the PartID. Its RowSource property has the following: